Generally, this invention relates to lightning rods and warning systems that provide safety features when used around human beings. A safe lightning rod can be utilized to reduce the danger to humans working near lightning rods. Specifically, this invention relates to a variety of lightning rod components and configurations that have been particularly engineered to perform in relation to human parameters.
The primary purpose of lightning rod assemblies is to transmit electrical charges safely to ground and away from the structure on which they are mounted. As a consequence, the top of the unit must be properly sized and shaped to be conducive to a lightning strike and the appropriate materials must be selected to allow for conductivity.
One of the unresolved problems in the field has been to engineer a lightning rod or charge dissipator with a shape that is both conducive to a lightning strike and simultaneously minimizes the danger to humans from injury or impalement resulting from falling upon or striking the projecting terminal of the lightning rod.
Present configurations for lightning rods encompass terminal elements which taper to a long thin tip or to a point similar to those disclosed in U.S. Pat. No. Des. 305,309; U.S. Pat. Nos. Des. 305,104; 4,540,844; and 4,752,85 which pose significant impalement hazards to humans. Even when an air terminal tip is blunted or slightly rounded the air terminal may be an impalement hazard. Other lightning rod configurations have non-contiguous surfaces in which appendages such as fingers may be trapped or severed as disclosed in U.S. Pat. No. Des. 361,289. Additional lightning rod configurations terminate in non-hebetative edges that pose severe laceration hazards as disclosed in U.S. Pat. Nos. Des. 361,289 and 4,760,213.
Another problem with respect to lightning rod systems is that national safety standards for the design and engineering of lightning rods which address the prevention of human impalement or injury are only recently in the process of being formulated. As such, the shaft (or electrically conductive rod) and the terminal portion of lighting rods may not be engineered to be either deformable or force spreading in response to the application of the usual forces generated when a human of average size and weight falls upon or strikes the terminal portion of a lightning rod. As a result, humans which fall upon a lightning rod terminal are at increased risk of injury or impalement because the appropriate preventative safety features may be lacking.
At least two problems have presented themselves from the consumer""s perspective. First, is the need for a lightning rod system or lightning rod system components to retrofit existing lightning rods which upon installation limit potential liability from impalement or injuries to humans. Such a lightning rod system would be engineered in anticipation of those conditions which are typical for humans working near lightning rods mounted to buildings or other structures. Although, the dangers of impalement have been known and mitigated in other workplace environments for almost two decades as disclosed by U.S. Pat. Nos. 4,202,378 and 4,308,701 until the instant invention the use of a humanized engineering standard with respect to lightning rods was not achieved and the dangers of impalement had remained unresolved.
A second problem from the consumers perspective was obtaining a simple low cost lightning rod system for the protection of buildings or structures. To some degree those in the field were lead away from the solutions of the present invention. Improved lightning rod systems have generally included additional and more complicated parts as disclosed by U.S. Pat. No. 4,910,636 showing a multiplicity of fine wires which may become entangled, broken off, or deformed (also note that the support rod for the multiplicity of wires remains and impalement hazard); or as disclosed by U.S. Pat. No. 4,760,213 and U.S. Pat. No. Des. 361,289 which both incorporate elaborate hollow shells and the latter also including brush elements held within the shell. To the extent that this approach lead innovators to believe that this additional complexity was necessary to achieve adequate lightning protection for buildings teaches away from the less complex and economical approach of the instant invention.
Accordingly, the present invention provides lightning rod systems and warning systems having components specifically engineered to be both inexpensive and less complicated and yet, remain responsive to the impact of a falling human.
As one example of the danger of present lightning rods, imagine a worker on a rooftop carrying tools across the roof. The roof is comprised of a lightning protection system with many Franklin type lightning rods distributed across the rooftop. Now, imagine the worker tripping over a cable on the rooftop and falling on one of the lightning rods. Serious injury, such as the worker being impaled on the lightning rod, could easily result from impacting a traditional Franklin lightning rod or other conventional lightning rod system. As such, the broad goal of this invention is to incorporate safety features into lightning rod systems and warning systems to minimize the risk of impalement upon or the injury from the projecting air terminal of the lightning rod.
A surprising aspect of this invention was discovered in ascertaining the appropriate types of engineered components to incorporate as safety features to the lightning rod systems and warning systems. From these efforts, it has been discovered that both the electrically conductive end cap and the electrically conductive rod may incorporate engineered features such that they may be used either separately or in tandem to remediate impalement or minimize injury to a human from falling on the air terminal of a lightning rod system.
With respect to the electrically conductive end cap, one object of the invention was to engineer a contiguous hebetative impact surface having force disseminating termini which could be substantially centered over the end cap on the projecting air terminal. The surface area of contiguous hebetative impact surfaces and termini may be sufficient to effectively spread the impact force of a falling human such as to prevent impalement of a human and minimize injury even if the rod supporting the hebetative impact surface does not deform upon impact. Many examples of non-contiguous surfaces exist including those shown in U.S. Pat. No. 4,760,213; U.S. Pat. No. Des. 305,104; U.S. Pat. No. Des. 361,289. Openings such as those shown in the above mentioned patents present areas in which appendages such as fingers can be caught and possibly severed. Moreover, these openings may provide access to the interior of the lightning rod assembly where additional components may also provide cutting or catching surfaces such as the brush elements in U.S. Pat. No. Des 361,289. Also, as can be understood from these same United States Patents, the terminal edges of the lightning rod components may not be sufficiently rounded to disseminate impact forces. Rather, it may be the case that the termini present potentially lacerating edges or have long tapered or pointed projections. These types of surface features which are generally believed to be necessary to initiate a lightning strike teach away from the broad goal of this invention which is to provide a lightning rod having an air terminal with a contiguous hebetative surface having force disseminating termini substantially centered over the lightning rod. The exact size and shape of the contiguous hebetative surface may vary based upon whether or not it is used in conjunction with other components, such as the rod, which are standardized to human parameters.
A related object of the invention is to remediate the impalement and injury hazard of existing lightning rods by retrofitting the projecting air terminal with an solid end cap having a electrically conductive contiguous hebetative impact surface substantially centered over the solid end cap. The ability to retrofit existing lightning rods may allow wide spread use of this safety feature in a manner that is both inexpensive and practical.
With respect to the electrically conductive rod, one object of the invention is to provide a humanized quantal rod which remains in the undeformed configuration in response to forces typically encountered in day to day use but deforms when a human inadvertently falls upon it or strikes it. By defining the quantal deformation force as equivalent to that generated by a human of average size and weight falling from the surface on which the rod is attached onto the projecting air terminal surface of the rod without impalement, the rod is appropriately humanized to afford the appropriate level of safety for humans having to work near air terminal projections of lightning rods. As can be easily understood, the humanized quantal deformation threshold force may even vary with the size of the contiguous hebetative impact surface provided.
Yet another broad goal of the invention is to incorporate the above mentioned technologies into a warning air terminal system. This aspect of the invention, although not directly related to the protection of buildings from lightning strikes, utilizes the discovered technology above mentioned in conjunction with visibility enhancement materials to provide a warning system which minimizes impalement or injury hazard.
Still another goal of this invention is to provide the consumer with a lightning rod system which is both inexpensive and easy to use while limiting the potential liability associated with injuries acquired from humans inadvertently falling upon or striking projecting air terminals. With respect to this goal, the instant lightning rod system provides basic components which are readily assembled and have low maintenance costs and also include the above mentioned safety features.
Naturally further objects of the invention are disclosed throughout the specification and claims.